Question

我必须创建一个触发器来添加NoOfCustomers＆＃39;进入STORE表。如果客户数量大于限制，则会显示错误消息。我收到了错误＆＃34;错误的绑定变量＆＃39; NEW.NOOFCUSTOMERS＆＃39;＆＃34;当我试图运行触发器时，我似乎找不到原因。

CREATE OR REPLACE TRIGGER NoOfCustomersTrigger 
      BEFORE INSERT ON STORE
      FOR EACH ROW 
      DECLARE V_CAPACITY SHOPS.LIMIT%TYPE;
    BEGIN 
          SELECT LIMIT INTO V_LIMIT
          FROM SHOPS, SERVES
          WHERE CUSTID = SERVES.CUSTID AND STORENO = :NEW.STORENO;
          IF (:NEW.NOOFCUSTOMERS > V_LIMIT) THEN 
            RAISE_APPLICATION_ERROR (-20004,'The Number of Customers exceeds the LIMIT'); 
          END IF; 
        END;

Answer 1

您的代码中似乎存在一些错误，

在声明部分而不是V_LIMIT中使用V_CAPACITY，因为您在代码中使用v_limit。
sql语句将抛出column ambiguously defined错误，列必须引用为TABLE.COLUMN_NAME或TABLE_ALIAS.COLUMN_NAME。

试试这个，

CREATE OR REPLACE 
TRIGGER noofcustomerstrigger 
      BEFORE INSERT ON STORE
      FOR EACH ROW 
DECLARE v_limit shops.LIMIT%TYPE;
BEGIN 
     SELECT LIMIT INTO v_limit
     FROM shops A, serves b
     WHERE A.custid = b.custid AND storeno = :NEW.storeno;

     IF (:NEW.noofcustomers > v_limit) THEN 
          raise_application_error (-20004,'The Number of Customers exceeds the LIMIT'); 
     END IF; 
END;

Oracle SQL错误PLS-00049：错误的绑定变量'NEW.NOOFCUSTOMERS'

1 个答案: